Apparatus for extinguishing fires



J y 1, 1 M. BETZLER 2,841,227

APPARATUS FOR EXTINGUISHING FIRES Fqlled May 31, 1955 l mmw 2,841,227 APPARATUS FOR EXTINGUISHING FIRES Martin Betzler, Urach, Germany, assignor to Minimax Aktiengesellschaft, Stuttgart-Wurttemberg, Germany Application May 31, 1955, Serial No. 512,028 2 Claims. 01. 169-1) The invention refers to an apparatus for extinguishing fires and more especially to a method and apparatus for extinguishing fires in which a powder-like extinguishing medium is discharged with the aid of a fluid propellant under pressure, for example, a gaseous propellant to the seat of the fire to be extinguished.

. There is a tendency at the present time in fire fighting .technique to use especially fine-grained extinguishing States Patent example, on air fields. It has been found in practice that the flowing capacity of the dry powder is substantially reduced, since the powder agglomerates as a result of the shocks of the vehicles and the vibrations of the motor, and this results in certain circumstances in the breakdown of the apparatus. The fine-grained powder loses its flowing capacity, especially after having been stored for a longer time, more than is the case with the coarse-grained powder, and this occurs to a greater extent the higher the level of the stored powder is and the more this powder is agglomerated because of the shocks of the vehicle. For this reason, the powder must be loosened before or during its use in order to avoid its caking and, therefore, the formation of lumps. However, the measures hitherto adopted to achieve this end, namely, introducing the propelling agent into the lower part of the container or distributing the propelling agent over the whole height of the container but not over its Whole width, and only in the vicinity of the points at which the pressurized gas emerges (since this cannot be done otherwise), do not leadto satisfactory results.

It is the main object of this invention to provide an apparatus of the general character described by means of which a good loosening of the extinguishing powder is obtained so that lumps cannot form any more.

Another specific object of the invention is to provide an apparatus whereby on sudden substantial variations of the pressure above the level of the extinguishing powder there is exerted upon each individual little grain in the container of the extinguishing medium a force which separates the said grain from the adjacent grains, the size of the grains of the extinguishing medium being thereby no consideration because the propellant introduced into the container for the extinguishing medium envelops each individual grain of powder or each crystal on all sides.

With these and other objects in view which will appear as the description proceeds the invention consists of certain novel features as will be particularly pointed out in the appended claims.

Two forms of apparatus suitable for carrying out a method of the present invention are shown by way of example only in the accompanying drawings, in which:

2,841,227 Patented July 1, 1958 Figure 1 shows a side view of one form of apparatus,

Figure 2 shows a side view of the upper part of a moclified form of the apparatus of Figure 1.

In the apparatus according to Figure 1 the container 1 for the extinguishing medium is provided with a member 2 for rapid operation, for example, a hand-operated tap, upon the operation of which a part of the propellant in the container 1 can escape into the atmosphere; 3 is the container for the propellant which is connected with the container 1 by means of a pipe 4; 5 is the tube or hose [provided with a nozzle 6 which can be sealed. This arrangement is distinguished by an especially simple con struction. By rapidly opening the member 2 the pressure of the propellant is suddenly substantially reduced so that the extinguishing powder is well loosened.

However, when determining the total amount of the propellant to be used there must also be taken into consideration the fact that the propellant escaping from the container 1 during the sudden change of pressure can no longer be used to expel the extinguishing medium.

For this reason, when it is important that the total amount of the propellant should be made use of, there may conveniently be used the apparatus shown in Figure 2, in which the member 7 capable of rapid operation, which, for example, can be constituted by a frangible membrane which is ruptured when a predetermined pressure is attained in the container for the fire extinguishing medium, is connected with an auxiliary container 8 for receiving the propellant escaping therefrom.

By means of the auxiliary container the capacity of the container for the propellant is, therefore, increased, so that the total amount of the propellant can be used in this case to expel the extinguishing medium.

When using the auxiliary container, the pressure can also only once he suddenly varied, but the propellant in a the auxiliary container can be used later to expel the extinguishing medium when the pressure falls during operation. When there is provided a tap in lieu of a frangible membrane, this tap can be closed, and the tap it; of the auxiliary container 8 can be opened when the container 9 is half full so that the propellant in the auxiliary container can be discharged. After closing the tap 10 the pressure in the container 9 can be again suddenly changed upon an eventual'subsequent operation of the apparatus so that the extinguishing powder is loosened. Conveniently, the tap it) is arranged on the under side of the auxiliary container 3 in order that extinguishing powder carried along by the propellant penetrating through the ruptured membrane 7 into the auxiliary container 8 can be discharged.

As already explained above, the member capable of rapid operation can consist of a frangible membrane which is destroyed when a predetermined pressure in the container for the extinguishing medium is attained which thereby permits a part of the propelling agent to escape from this container. Naturally, any other seaiing member which opens automatically can be used as a member capable of rapid operation. In devices which contain several containers for the extinguishing medium there can be allotted, under certain circumstances, to sole auxiliary container at least two containers for the extinguishing medium.

The sudden change of pressure can be, for example, an increase in pressure. The new method of the present invention can also generally be used to loosen powder-like material in containers under pressure.

The foregoing description is directed solely towards the examples illustrated, but I desire it to be understood that I reserve the privilege of resorting all changes to which the invention is susceptible, this latter being defined and limited only by the terms of the appended claims.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

1. An apparatus for extinguishing fires with fire extinguishing powder propelled, by a propellant gas comprising a main container for the fire extinguishingrpowder,

means for operatively connecting said main; container to a propellant gas supply, an auxiliarycontainer, normally maintained at a substantially lowerpressure. than the propellant gas supplied to the main container, said. auxiliary container being connected tosaid main C0117.

tainer over a conduit containing a closure adapted and arranged to permit sudden communication betweenthe main container and said auxiliary containerthroughsaid conduit to elf'ect a sudden substantial loweringof the.propellant gas pressure in the main container: toloosen the References Cited in the file of this patent UNITED STATES PATENTS 1,009,980 Leisure et al. Nov. 28, 1911 1,991,403 McManaInna Feb. 14, 1935 2,120,297 Reinecke June 14, 1938 2,681,115 Guise June 15, 1954 2,690,229 Guise Sept. 28, 1954 

